A generic service switching device may be, for example, a line circuit breaker which comprises at least one contact point within its housing having at least one fixed and one moveable contact piece, via which contact point a current path leading from an input terminal to an output terminal can be opened and closed. The contact point is generally actuated by a switching mechanism with a latching point. Such a line circuit breaker may furthermore comprise tripping apparatuses, for example a thermal release or a magnetic quick-action release, which, in the event of a short-circuit current or residual current in the current path, act on the contact point or the switching mechanism so that the contact point is opened.
In Germany, a so-called standard module width of 17.5 mm has been passed for the installation width of line circuit breakers.
A generic service switching device may also be, however, an auxiliary switch for attachment to a line circuit breaker. Such attachment auxiliary switches are switched at the same time as the main poles and serve the purpose of disconnecting or connecting circuits. They can be used for many purposes, for example for switching optical or acoustic signals, which indicate the switching state of the main circuit. Auxiliary switches can have, in separate current paths, a plurality of auxiliary contacts, which are DC-isolated from one another and to which in each case one or two connecting conductors can be connected on the incoming and outgoing side. The attachment auxiliary switches generally only take up a width of half the standard module width, i.e. approximately 8.75 mm.
For connection to external connecting conductors, screw terminals are used in generic service switching devices. Single-module devices have also been disclosed in which screwless terminal connections are used on the outgoing side. In this case, plug-type terminals or spring-loaded terminals can be used as the clamping elements. In principle, these can considerably simplify the connection of connecting conductors since it is no longer necessary to fasten a screw using a screwdriver during fitting but instead the connecting conductor can be simply inserted into the terminal and is then held fixedly by the terminal element itself. If it is intended for more than one connecting conductor to be connected by means of a clamping element, each of the connecting conductors needs to be capable of being inserted and removed again without influencing the other connecting conductors.
EP 1 575 130 has disclosed a terminal connection in which a plurality of plug-type openings are provided in a contact frame. The clamping spring is split at its free end into a number of finger-like protrusions which corresponds to the number of plug-type openings by means of one or more slot-shaped cutouts. Each of the protrusions is passed through in each case one of the plug-type openings, and a conductor can be clamped fixedly in each of the plug-type openings by in each case one of the protrusions. Thereby each connecting conductor can be inserted and removed without influencing the other connecting conductors. In the case of a terminal connection in accordance with EP 1 575 130, only one narrow web is provided on the contact frame for the current path from a clamped-on connecting conductor to an outgoing conductor in the interior of the device. The transfer resistance from the clamped-on connecting conductor to the further electrical outgoing conductor into the switching device is correspondingly high. Since a dedicated connection window, separated by a transverse web, is available for each connecting conductor to be clamped on, the terminal connection in accordance with EP 1 575 130 is so wide that it does not fit into switching devices with only half the standard module width.